The head of the Environmental Protection Agency (EPA), Dr Mary Kelly, made the call yesterday after new figures showed that the recession, the collapse of the construction industry and more fuel-efficient cars resulted in emmissions plummeting by nearly 8pc in 2009.

Emissions from cement plants alone have fallen by a massive 38pc, the EPA said.

The drop means the State is unlikely to be required to buy any more carbon credits to meet the emission targets set out in the Kyoto Protocol for 2012.

Ireland has already bought eight million credits, but will only need to use 6.2 million. The rest can be sold or used at a future date.

The EPA said overall emissions fell by 5.4 million tonnes to 62.32 million tonnes in 2009 -- a reduction of 7.9pc. Industrial and commercial emissions fell by 20pc, energy by 10.7pc and transport by 7.7pc.

Greenhouse-gas emissions are the primary cause of climate change or global warming. Scientists warn that unless we reduce the amounts being emitted, a tipping point will be reached beyond which the climate cannot recover.

But the EPA warned that the downturn should be used to implement 'green' policies, so that more onerous targets, which are on the way from the EU, will be met.

"The magnitude of the reduction in Ireland's emissions is unprecedented," Dr Kelly, the EPA director-general, said.

"In particular, the 20pc cut in emissions from the industrial and commercial sector reflects the impact that the severe economic recession is having.

Stringent

"We need to use this opportunity to embed fundamental emission reductions in order to meet the very stringent EU limits for 2020 which we face."

She added: "We need to move permanently to a low-carbon economy and should not rely on a recession to meet our targets in the future."

By 2012 under the Kyoto Protocol, Ireland will be allowed to produce just 55.6 million tonnes a year.

The EPA says these targets will be met because of improvements in the energy efficiency of homes and more fuel-efficient cars, including the rollout of electric vehicles.

Some 15pc of Ireland's energy needs last year were met by renewable energy, which also reduce the amount of fossil fuels being burnt to produce electricity.

Brian Motherway, of the Sustainable Energy Authority of Ireland, said: "The changes to motor tax, benefiting more fuel-efficient cars; the carbon tax; uptake in renewables; and more efficient buildings will really wash in during 2010."